Roger Shaler Bagnall (born August 19, 1947 in Seattle) is an American classical scholar. He was a professor of classics and history at Columbia University from 1974 until 2007, when he took up the position of first Director of the Institute for the Study of the Ancient World (ISAW) at New York University.

Born in Seattle, Washington, Bagnall studied at Yale University (B.A., 1968) and University of Toronto (M.A., 1969; Ph.D., 1972). He has published several works on the history of Ancient Greece and Ancient Egypt, as well as papyrology. He was elected a Fellow of the American Academy of Arts and Sciences in 2000.

Most of the everyday writing from the ancient world - that is, informal writing not intended for a long life or wide public distribution - has perished. Reinterpreting the silences and blanks of the historical record, leading papyrologist Roger S. Bagnall convincingly argues that ordinary people - from Britain to Egypt to Afghanistan - used writing in their daily lives far more extensively than has been recognized. Marshalling new and little-known evidence, including remarkable graffiti recently discovered in Smyrna, Bagnall presents a fascinating analysis of writing in different segments of society. His book offers a new picture of literacy in the ancient world in which Aramaic rivals Greek and Latin as a great international language, and in which many other local languages develop means of written expression alongside these metropolitan tongues.